Perineural Dexamethasone Prolongs the Duration of Combined Femoral and Sciatic Nerve Block in Lower Limb Vascular Surgeries: A Prospective Randomized Trial

Background: Lower limb vascular surgeries are usually associated with significant postoperative pain. The widespread use of regional anesthesia, especially peripheral nerve blocks, provides effective postoperative analgesia together with considerable cardiovascular stability. Different additives have been used to prolong regional blockade. However, the results are either inconclusive or associated with side effects. The use of perineural steroids in peripheral nerve blocks is reported to augment postoperative analgesia, without evidence of adverse effects.Methods: Fifty-six adult patients, scheduled for lower limb vascular surgery, were randomly allocated into one of the two study groups:•Group D (Dexamethasone group): 28 patients received 20ml bupivacaine 0.5% plus 2ml (8mg) dexamethasone in each block.•Group C (Control group): 28 patients received 20ml bupiv acaine 0.5% plus 2ml normal saline 0.9% in each block.The study aimed at detecting a significant difference, on using adjuvant perineural dexamethasone, as regards the duration of sensory blockade, as the primary outcome. Other parameters were considered as secondary outcomes, including the duration of analgesia, onset of sensory and motor blockade, the duration of motor blockade, as well as changes in heart rate, arterial blood pressure, respiratory rate, and oxygen saturation.Results: Demographic data did not show a statistically significant difference between the two studied groups. No significant difference was shown between patients of both groups, regarding sensory and motor block onset. Significant prolongation of sensory and motor blockade, as well as duration of analgesia was recorded in patients of group D, when compared to group C. Results also showed statistically significant lower postoperative pain scores in patients of the dexamethasone group when compared with the control group. The nerve block administered was successful in all patients of the studied groups. None of the patients reported any block-related complications.Conclusion: The adjuvant use of perineural dexamethasone in combined femoral and sciatic nerve block, for patients undergoing major vascular surgeries, is associated with extended duration of sensory and motor blockade, prolonged postoperative analgesia, and reduced postoperative pain scores. Meanwhile, the onset of sensory and motor blockade was not significantly affected.